Between 1872 and 1890, three closely related reactions that involve a stereoselective (or stereospecific) rearrangement of an alkyl group from an acyl carbon to nitrogen were reported by Wilhelm Clemens Lossen, who reported a base-promoted rearrangement of hydroxamic acid derivatives, by August Wilhelm von Hofmann, who reported the base-promoted rearrangement of N-haloamides, and by Geheimrat Julius Wilhelm Theodor Curtius, who reported the rearrangement of acyl azides.